参数资料
| 型号： | FSFA2100 |
| 厂商： | Fairchild Semiconductor |
| 文件页数： | 12/16页 |
| 文件大小： | 0K |
| 描述： | IC SWIT OVP UVLO 9SIP |
| 标准包装： | 19 |
| 输出隔离： | 隔离 |
| 频率范围： | 94 ~ 106kHz |
| 输入电压： | 14.5 V ~ 25 V |
| 输出电压： | 650V |
| 功率（瓦特）： | 200W |
| 工作温度： | -40°C ~ 130°C |
| 封装/外壳： | 9-SIP |
| 供应商设备封装： | 9-SIP |
| 包装： | 管件 |
| 产品目录页面： | 1222 (CN2011-ZH PDF) |
capacitor C SS remains fully discharged. After power-on,
C SS becomes charged progressively by the current
through the R T pin, which determines the operating
frequency. The current through the R T pin is inversely
proportional to the total impedance of the connected
resistors. The total impedance at startup is lower than
that of the normal operation because R SS is added on
R SET in parallel, which means the operating frequency
decreases continuously from higher to nominal.
Eventually C SS is fully charged to the R T pin voltage and
the operating frequency is determined by R SET only.
During the charging time of C SS , the operating frequency
is higher than during normal operation. In asymmetric
half-bridge converters, a switching period contains
powering and commutation periods. The energy cannot
be transferred to the output side during commutation
period. Since the DC link voltage applied to the V DL pin
and the leakage inductance of the main transformer are
fixed, the powering period over the switching period is
shorter in high switching frequencies. As C SS is charged,
the switching frequency decreases and the powering
period over the switching period increases as well. It is
helpful to start SMPS softly with the internal soft-start
time together.
For the high-side MOSFET, a long duty cycle and high
applied voltage make an excessive primary current.
When the high-side MOSFET turns off, the primary
current flows back to the DC link capacitor through the
body diode of the low-side MOSFET. It keeps the same
status even after turning on and off the low-side
MOSFET. When the high-side MOSFET turns on again,
a huge current can flow from the DC link capacitor
through the channel of the high-side MOSFET and body
diode of the low-side one due to the reverse recovery. It
may induce unexpected noise into CS pin.
To avoid this issue, the voltage across the DC blocking
capacitor must be low enough. In general, two resistors
with several MHz can be added on the drain-to-source
terminals of each MOSFET to divide the DC link voltage.
6. Burst Operation : To minimize power dissipation in
standby mode, the FSFA2100 enters burst-mode
operation. As the load decreases, the feedback voltage
decreases. As shown in Figure 25, the device
automatically enters burst mode when the feedback
voltage drops below V BL (1.3 V). At this point, switching
stops and the output voltages start to drop at a rate
dependent on standby current load. This causes the
feedback voltage to rise. Once it passes V BH (1.5 V),
switching resumes. The feedback voltage then falls and
the process repeats. Burst-mode operation alternately
enables and disables switching of the MOSFETs, thereby
reducing switching loss in standby mode.
V O
Vo set
V FB
1.5V
1.3V
I ds
Figure 24. External Soft-Start Circuit
5. Startup: Due to the imbalance of the turn-off
resistance between the high- and low-side MOSFETs,
the voltage across the DC blocking capacitor cannot be
predicted at startup. Additionally, the high-side MOSFET
starts with a large duty cycle since the duty cycle of the
V ds
low-side MOSFET increases step-by-step during soft-
start time. Therefore, in the case where high voltage is
already charged in the DC blocking capacitor due to the
higher turn-off resistance of the high-side MOSFET
t 1
Switching
stop
t 2
t 3
Switching
stop
t 4
t
before startup, a large primary current could flow through
the high-side MOSFET during turn-on time after startup.
? 2008 Fairchild Semiconductor Corporation
FSFA2100 ? Rev. 1.0.1
12
Figure 25. Burst-Mode Operation
www.fairchildsemi.com
相关PDF资料 |
PDF描述 |
|---|---|
| FSFM261N | IC PWM/SENSEFET FPS 8-DIP |
| FSFR1600L | IC FPS POWER SWITCH 9-SIP |
| FSFR1600XSL | IC FPS PWR SWITCH 160W 9-SIPL |
| FSFR1700XSL | IC FPS PWR SWITCH 200W 9-SIPL |
| FSFR1800HSL | IC FPS HALF BRIDGE RES CONV 9SIP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| FSFD 10-0.5 | 制造商:TURCK Inc 功能描述:Sensor Connector 制造商:TURCK Inc 功能描述:SENSOR CONNECTOR; Cable Length:0.5m; Connector Mounting:Panel; Connector Type:Sensor; Contact Material:Brass; Contact Plating:Gold; Contact Termination:Solder; Gender:Plug; No. of Contacts:10; No. of Positions:10; Series:Eurofast ;RoHS Compliant: Yes |
| FSFD 10-1.0 | 制造商:TURCK Inc 功能描述:Receptacle, Rear Mount with Leads, 10X24 AWG |
| FSFD 12-0.5 | 制造商:TURCK Inc 功能描述:U0910-93 制造商:TURCK Inc 功能描述:Sensor Connector 制造商:TURCK Inc 功能描述:SENSOR CONNECTOR; Cable Length:0.5m; Connector Mounting:Panel; Connector Type:Sensor; Contact Material:Brass; Contact Plating:Gold; Contact Termination:Solder; Gender:Receptacle; No. of Contacts:12; No. of Positions:12 ;RoHS Compliant: Yes |
| FSFD 4.4 | 制造商:TURCK Inc 功能描述:FSFD 4.4 |
| FSFD 4.4-0.5 | 制造商:TURCK Inc 功能描述:Connector; Receptacle; 4; 22 AWG; PG 9; 4 A; 250 V; Brass; Nickel Plated Brass 制造商:TURCK Inc 功能描述:SENSOR CONNECTOR 制造商:TURCK Inc 功能描述:SENSOR CONNECTOR; For Use With:Sensors; Accessory Type:Cordset; Cable Length:0.5m; Cable Length - Imperial:1.64ft; Cable Length - Metric:500mm; Connector Mounting:Panel; Connector Type:Sensor; Connector Type B:Free / Stripped End ;RoHS Compliant: Yes |
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